By the end of 2018, 55 million U.S. smartphone users over the age of 14 will make a mobile payment at a retail store. Out of them, 23.4 million people will use coffee company Starbucks’s mobile payment app. This is the new forecast by research firm eMarketer.

Starbucks is well ahead of competitors Apple Pay, Google Pay, and Samsung Pay. According to the estimate for 2018, Apple Pay will be used by 22 million users and Google Pay by 11.1 million. eMarketer expects that Starbucks will continue to lead up to 2022.

Starbucks’ achievement is mainly because the company has been able to connect the payment app with the company’s loyalty rewards program. Users can easily transfer their Starbucks gift cards to the mobile payment app. By deciding to pay through the app, users not only save time and money, but also take advantage of the special discounts from Starbucks.

eMarketer expects that although the number of users will increase for the top four service providers, their market share will diminish because of competition from new mobile apps launched by retailers.